Delete py2 checks

No script can run on py2 (due to print syntax change), so those
checks are useless (will never be printed).

Change-Id: I9cc7bc8b2665dd09cc7f8939ba255956f96af88a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/5262958
Commit-Queue: Josip Sokcevic <sokcevic@chromium.org>
Reviewed-by: Gavin Mak <gavinmak@google.com>

gclient.py

@@ -4103,11 +4103,6 @@ def path_contains_tilde():
 
 
 def can_run_gclient_and_helpers():
-    if sys.version_info[0] < 3:
-        print('\nYour python version %s is unsupported, please upgrade.\n' %
-              sys.version.split(' ', 1)[0],
-              file=sys.stderr)
-        return False
     if not sys.executable:
         print('\nPython cannot find the location of it\'s own executable.\n',
               file=sys.stderr)

gerrit_client.py

@@ -511,11 +511,6 @@ class OptionParser(optparse.OptionParser):
 
 
 def main(argv):
-    if sys.version_info[0] < 3:
-        print('\nYour python version %s is unsupported, please upgrade.\n' %
-              (sys.version.split(' ', 1)[0], ),
-              file=sys.stderr)
-        return 2
     dispatcher = subcommand.CommandDispatcher(__name__)
     return dispatcher.execute(OptionParser(), argv)
 

git_cl.py

@@ -6689,12 +6689,6 @@ class OptionParser(optparse.OptionParser):
 
 
 def main(argv):
-    if sys.version_info[0] < 3:
-        print('\nYour Python version %s is unsupported, please upgrade.\n' %
-              (sys.version.split(' ', 1)[0], ),
-              file=sys.stderr)
-        return 2
-
     colorize_CMDstatus_doc()
     dispatcher = subcommand.CommandDispatcher(__name__)
     try:

my_activity.py

@@ -53,10 +53,6 @@ import fix_encoding
 import gclient_utils
 import gerrit_util
 
-if sys.version_info.major == 2:
-    logging.critical(
-        'Python 2 is not supported. Run my_activity.py using vpython3.')
-
 try:
     import dateutil  # pylint: disable=import-error
     import dateutil.parser

win_toolchain/package_from_installed.py

@@ -500,9 +500,6 @@ def RenameToSha1(output):
 
 
 def main():
-    if sys.version_info[0] < 3:
-        print('This script requires Python 3')
-        sys.exit(10)
     usage = 'usage: %prog [options] 2022'
     parser = optparse.OptionParser(usage)
     parser.add_option('-w',